A packet may need to pass through a forwarding device when being transmitted in a network. A latency may be generated when the packet passes through the forwarding device. A latency of the packet in a transmission path may include the latency generated when the packet passes through the forwarding device. Latencies generated when different packets pass through the forwarding device may be unequal. Therefore, latencies of the different packets in a transmission path may be unequal.
The foregoing case may be caused because processing performed by the forwarding device on the different packets is different. For example, when the forwarding device performs table lookup operations according to the different packets, time intervals needed for the table lookup operations corresponding to the different packets may be unequal.
A phenomenon that latencies of different packets in a transmission path are unequal may be referred to as latency variation. Latency variation is unacceptable for some services. For example, a CPRI (Common Public Radio Interface) service, an SDH (Synchronous Digital Hierarchy) service, or a PDH (plesiochronous digital hierarchy) service that is transmitted between a BBU (Baseband Unit) and an RRU (Remote Radio Unit) imposes a strict requirement on a latency of a packet.
In the prior art, a latency generated when a packet passes through a forwarding device cannot be enabled to be equal to a certain value.